wireless connections

Since two weeks I'm experiencing slow speeds on my laptop, the speeds of my other laptops are fine tho. Speedtest result of this laptop: http://beta.speedtest.net/result/6577820767 Speedtest result of my other laptop: http://beta.speedtest.net/result/6577805937 I'm not sure why this laptop...

I have 3 computers in my Homegroup, all running Win7 Pro. A week ago, the cptr I use lost connection with the Homegroup. I can see the other computers on Network on Win Explorer, but when I click on them, they want a User Name and Network Password, which I don't have. I think I've discovered...